Other Pediatric Obstructive Disease

Question 1

What is bronchiolitis?

Answer 1

• Mech - inflammation and stenosis of bronchioles –> diffuse SMALL airway obstruction
• Source of Resistance - narrowing of lumen from inflammation, edema and/or deposition of connective tissue in airway wall or lumen
• Cause varies by age
  
  • Infants/toddlers - viral infection; self-limited (RSV, flu, adenovirus, HMV) or mycoplasma pneumoniae in kids up to age 5
  • Adults - underlying connective tissue disorder, toxin exposure; CHRONIC

Question 2

RSV

Answer 2

• Lower tract infections from RSV = #1 cause of hospitalization in kids under 1yo in US
• Usually annual outbreaks bc Oct-April (varies by region - earlier in south)
• Sngl stranded RNA virus

Question 3

RSV Course of Infection

Answer 3

• Enters via nasal/conjunctiva –> upper airway infection –> prod/circulate antibodies
• THEN secretions aspirated into lower airway –> enter epithelial cells, replicate, kill/lyse cell –> release virus and inflammatory mediators –> lymphocyte infiltrate, edema, inc secretions and debris in airway

Question 4

RSV Infection Symptoms

Answer 4

• thin, clear rhinorrhea, retractions, crackles, hypoxemia from V/Q mismatch, rapid shallow breath (low compliance, high resistance), atelectasis and inc interstitial marking on imaging

Question 5

Viral Bronchiolitis Dx

Answer 5

• Dx - Nasopharyngeal or aspirate specimen; viral culture (gold std) or faster ELISA/PCR

Question 6

RSV Tx

Answer 6

• Tx - mainly fluids and supplemental oxygen (no anti-viral b/c done replicating by the time of presentation);
• hospitalize esp if cyanotic, unable to drink, parents overly distressed
• May use bronchodilators or steroids to overcome symptoms

HANDWASHING TO PREVENT

Question 7

Palavizumab

Answer 7

prophylaxis if at high risk of RSV; antibody against F (fusion) proteins of RSV

Question 8

Bronchopulmonary Dysplasia

Answer 8

• Premature infants (“Chronic Lung Disease of Infancy”)
• See “ground glass” on X-ray
• Broad definition - need for supplemental oxygen at 36 wks post-conceptual age
• Premature infants survive w/ arrest of alveolar development (born at canalicular or early saccular stage) so few developed alveoli / no surfactant production
  
  • 24-28 wks gestation

Question 9

Management of BPD/CLDI

Answer 9

• Born w/ resp distress so need ventilation but use lower pressures to avoid injury
• Usually improves w/ time as lungs mature but in meantime…
  • Glucocorticoids - mature surfactant production
  • Caloric supplements - use more energy to breath
  • Supplemental oxygen - b/c hypoxemia can inhibit growth
  • Bronchodilators
  • Diuretics - dec interstitial edema (SIDE EFFECTS - alkalosis, nephrolithiasis, hypercalciuria)
  • Corticosteroids - anti-inflammatory (SIDE EFFECTS - growth fail, GI bleed, HTN)
  • Prevent viral infection (handwashing and flu shots)